Sardinia has a relatively confined electricity grid with limited interconnections to the mainland and, on the other hand, has high solar and wind power potential, offering viable options as laboratory for Smartgrid development scenarios. Keeping this in mind, the paper investigates the use of hydro pumping as a smart grid player to be used as flexible storage compensator for wind and solar generation in the Sardinian power transmission grid. By considering the current situation, and the energy outlook for 2020, in terms of demand and conventional and renewable generation, the paper investigates on the maximum renewable energy capacity that might be integrated into the Sardinian power system with a different exploitation of hydro pumping storage systems. Hydro pumping storage aims at obtaining the maximum integration of intermittent sources, such as wind and solar, by limiting the amount of renewable energy curtailments.